Ablation of prostaglandin E<sub>2</sub> signalling through dual receptor knockout in CAR T cells enhances therapeutic efficacy in solid tumours.

Dörr, Janina; Gregor, Lisa; Lacher, Sebastian B; Oner, Arman; Sun, Yi; Piseddu, Ignazio; Fertig, Luisa; Spajic, Sebastijan et al. · Nat Biomed Eng · 2026

basic_science · Level V

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Abstract

The efficacy of chimeric antigen receptor (CAR) T cell therapy in solid cancers is limited by immunosuppression in the tumour microenvironment (TME). Prostaglandin E<sub>2</sub> (PGE<sub>2</sub>) is a key factor locally inhibiting T cell function. We hypothesized that targeted ablation of PGE<sub>2</sub> signalling in CAR T cells may enhance their activity in PGE<sub>2</sub>-rich solid tumours. Here we generate knockout CAR T cells double deficient for the PGE<sub>2</sub> receptors EP2 and EP4 (EP2<sup>-/-</sup>EP4<sup>-/-</sup>) by CRISPR-Cas9 engineering. EP2<sup>-/-</sup>EP4<sup>-/-</sup> CAR T cells expanded unabatedly in the presence of PGE<sub>2</sub>. Further, they effectively controlled syngeneic and human xenograft tumour models in vivo, which was accompanied by intratumoural accumulation and persistence of modified T cells. Improved anti-tumour activity was also observed against patient-derived tumour samples from patients with pancreatic ductal adenocarcinoma (PDAC), colorectal (CRC) and neuroendocrine (NET) cancer. Our data uncovers the detrimental impact of PGE<sub>2</sub>-mediated suppression on CAR T cell efficacy and highlights EP2 and EP4 targeting as a potential strategy.

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